PURPOSE:Management of congenital and acquired anophtalmus in the pediatric patients is a challenging clinical problem for plastic and craniofacial surgeons. The absence of ocular globe during the period of facial growth has been associated with asymmetries that are difficult to reconstruct at later stages. In vivo animal studies in our institution suggested that pressure controlled orbital tissue expanders (PC-OTE) promotes development of near normal orbits in the anophtalmic kitten model. The aim of this study is to present the results of pediatric micro/anophtalmic patients treated with PC-OTE.

METHODS: Study received previous IRB approval. Animal Experiments: 25 kittens were divided into 5 different groups: Group I: non-operated; Group II: enucleation only; Group III: enucleation and insertion of a spherical 1ml implant; Group IV: enucleation and insertion of a 1ml spherical tissue expander (STE) inflated to 5 ml, Group V: enucleation and insertion of a 1 ml STE overinflated to 7.5ml. All animals were operated at 6 weeks of age. Intraluminal pressure was measured all groups. Orbital dimensions were measured clinically with calipers biweekly, and with CT scans every 3 weeks. At 26 weeks of age (completion of orbital growth), the animals were sacrificed, and skull preparations were analyzed. Clinical trial: 10 pediatric patients (age between 2 to 7 year old) with unilateral micro/anophtalmus of different origin were implanted a 1ml STE in the affected orbit. Eye lids were sutured together. Peripheral access port was placed in the subcutaneous tissue of the ipsilateral temporal area. STE underwent pressure controlled tissue expansion to reach a final 5ml volume. Orbital dimensions were measured clinically with calipers and with CT scans yearly. STE were left in place between 3 and 12 years. Upon removal of the STE, a permanent ocular prosthesis was placed.

RESULTS: Animal experiments: Growth curves showed that enucleated orbits alone (group II) and enucleated orbits containing spherical 1 ml implant (group III) showed an hypotrophic orbit when compared with controls. Enucleated animals treated with STE inflated to 5ml (normal cat eyeball size) (group IV) showed orbit dimensions what were not significantly different to controls. Peri-orbital facial bones (zygomatic arch, etc.) were similar to controls. Animals with over-expanded STE showed over expanded orbits and developed extrusion of the implants. Clinical trial: Clinical and CT scan growth curves of the anophtalmic pediatric patients treated with STE showed an orbital growth similar to the contralateral unaffected side. Facial bones and soft tissue appearance of the affected side was acceptable when compared with the unaffected side. No orbital tissue expander extrusion was observed.

DISCUSSION: Near normal orbital growth and bonny facial symmetry could be achieved in the anophtalmic kitten animal model using STE. Similar results could be achieved in the pediatric patients using similar pressure controlled tissue expansion technique. These results suggest that micro/anophtalmus related facial asymmetry could be managed/prevented with the use of PC-OTE in pediatric patients.